Interpretive Summary: Potato as a vegetable with large consumption in the US population can serve as an important source of nutrients where levels are high enough. We studied the calcium and magnesium contents of advanced breeding lines. Calcium and magnesium are considered macronutrients which need to be consumed in large amounts on a daily basis. Fortunately, foods usually contain abundant calcium and magnesium. In particular dairy products are the highest source of calcium. For the potato, calcium and magnesium are not often found to be lacking for proper growth. Calcium sufficiency, hwoever, has been found to be related to the physiological disorders called internal brown spot and heat necrosis in potato. In addition, resistance to a rotting bacterial pathogen is affected by available calcium. Our results have shown that it is likely that both calcium and magnesium can be increased by selection among variable breeding lines. The present status is that potato is not a significant source of either of these minerals in the human diet . After expected changes through breeding this status would not change. On the other hand differences in calcium and magnesium contents are more likely to be related to the potato plant's own health status and its ability to maintain quality and not be subject bacterial soft rot

Technical Abstract:
Calcium and magnesium are two minerals with prominent roles in animal and plant metabolism. Advanced potato breeding lines were found to contain between 266 and 944 µg per gram fresh weight of calcium and between 705 1089 µg per gram fresh weight of magnesium. All trials had significant genotype by environment interaction. However only the Western Regional Red/Specialty trials displayed a significant source of variation for genotypes for both minerals. In the Tri-State trials eight and four genotypes displayed significant G x E, while 6 and 3 remained unstable after removal of environmental heterogeneity for calcium and magnesium, respectively. In the Western Regional Russet trials ten and seven genotypes out of 13 had significant G x E, in calcium and magnesium contents, while nine and seven, respectively, remained unstable after removal of environmental heterogeneity. Finally, in the Regional Red/Specialty trials, eight and nine genotypes presented significant G x E, and five and four remained unstable when environmental stability was removed, for calcium and magnesium, respectively. In the Regional Red/Specialty calcium ranged from 266 to 453 µg per gram and magnesium ranged from 787 to 1089 µg per gram DW. Broad-sense heritabilities were non-zero for The Tri-State and Western Regional Russet trials for calcium and for Tri-State and Regional Red/Specialty trials for magnesium. Broad-sense heritability was high enough in the Tri-State trials to expect an increase in content for both calcium and magnesium after selection within these groups of clones for both. An increase in magnesium content would be also expected after selection in the Western Red/Specialty trial. Potato is not a rich source of either calcium or magnesium for the human diet, but differences in potato genotypes might be useful for potato crop health in regards to Calcium content.